One summer’s day I observed this White-lipped Snail Cepaea hortensis as it travelled from leaf to leaf on my crab apple tree. It was very slow going, but how it managed to slide and glide from leaf to leaf without falling off was quite something.
This is the Large Red Slug (Arion (Arion) rufus), and its slimy kind really like to set up camp in my garden to chomp on my plants. Now most people know if you want to reduce the slug population in your garden you can dig a hole in the ground and bury a small container of beer whereby the slugs will be attracted, fall in and will drown their sorrows, and themselves in the process. Another way is to sprinkle salt on them where they will meet a most horrible gooey death. However, contrary to them dying by salt, I came across this one munching on a crisp this afternoon on my back decking, which I thought was quite an odd thing to witness, to say the least.
This was a beef and onion crisp, yes it was salted, and it could not get enough of it. It devoured the lot, and mopped up any remaining crumbs in one sitting. After desert (too disgusting to mention) it casually slid off between a narrow crack in the decking.
I am always fascinated by the intricacies of shells, and how they have evolved to be so. I can’t help but gaze at the top image in wonderment, marvelling at the beauty and bio-engineering involved in its evolution over hundreds of millions of years. All this to protect and shelter the animal inside which had once been feasting on my garden plants.
Garden Snail (Cornu aspersum) rear garden, Staffordshire, England. August 2017.
After a fair bit of rain I can expect to find these snails out and about in the daytime, where usually they feed under the safe cover of darkness.
They can be a pest, especially to my bedding plants and the few vegetables I grow, and my Hosta which looks like it has been riddled with bullets. Yet I still find a fascination with these creatures, and how very well evolved they are for surviving on the land, as opposed to their seafaring cousins.
By the Mesozoic Era, some 248 million years ago, some of these gastropods had adapted in such a way they left the marine environment to live in freshwater and terrestrial habitats. And here they are now, munching through my garden after the June rain has fallen.
People maybe surprised to know that molluscs consist of the second largest group of animals on earth after the insects, with some 100,000 species plus. Of this group the gastropods are the largest of the mollusc group, with more than 50,000 species globally. They have been around for at least 500 million years. Their habitats can be marine, freshwater, estuarine, or terrestrial. Included in this class are the shell covered snails. limpets, sea hares, and the shell-less slugs.
The body of the snail consists of a large muscular foot, a visceral hump which is contained within an asymmetrically coiled shell (a univalve) a head with eyes and tentacles, and a mouth that contains a rasping tongue used to remove, crush and grind food. Most species of snail are herbivores, whilst others feed on live prey or carrion. They are mainly active at night so their bodies do not dry out in the sun, and during the day they hide in dark, damp places. Those with shells which not only give them some protection against predation, but also protection from desiccation, hide within them and seal themselves against rocks, stones, or vegetation.
Order: Stylommatophora (Air-breathing Terrestrial Slugs & Snails) This taxon, now considered to be a clade, is a very large group of pulmonate (air-breathing) land snails and slugs. They are characterised by having two pairs of retractile tentacles with eyes located on the tips of the larger tentacles.
Order: Basommatophora (Freshwater Snails) In this order are the air-breathing land snails which are found in ponds, ditches, streams, rivers and shallow lakes. They are characterised by having their eyes located at the base of their non-retractile tentacles, rather than at the tips, as in the true land snails in the order Stylommatophora. The majority of basommatophorans have shells that are thin, translucent, and which are fairly colourless.
Order: Neogastropoda (Whelks, Cones & Tritons) These gastropods are mainly deposit feeders or predators. They all have a well-developed siphon for detecting prey. The larger bottom-dwelling carnivores commonly feed on bivalve molluscs, other gastropods, sea urchins, polychaete worms, and even fish. They will often burrow into the sand to reach their prey.
Order: Neotaenioglossa (New Gastropods) This order of mollusc is believed to have evolved around 70 million years ago during the last days of the dinosaurs. They are characterised by the possession of only one gill, one auricle, one kidney and by siphon. This order is generally considered to be the most advanced of the prosobranch molluscs, which include the familiar whelks.
A pale, translucent slug which is greyish-buff colour, and has a pair of dark lines running along its sides. Length 60 to 90mm.
It can be seen all year-long, and is found in on trees, usually in wet weather. It produces large amounts of watery mucous when disturbed as a defence measure. Common and widespread in woodland in W Britain and Ireland.
Also called the ‘Brown Field Slug’, this has a translucent grey-brown body, although it may be darker. The mantle is usually tinged chestnut, and it usually, but not always, has a pale ring around its respiratory pore. It has a very short keel. The mucus is colourless. Quite a fast-moving slug. Length 25 to 35mm.
This slug can be a significant pest in gardens, allotments and nurseries and will eat many types of plants and seedlings.
Found in woods, but especially parks and gardens. Discovered under logs, stones and paving. Introduced to Britain and Ireland in the early 1930s, and has spread rapidly since 1975 and has become common and widespread.
I have shown the two gaper shells on one post to illustrate how different they are, beginning with the Sand Gaper above.
Sand Gaper (Mya arenaria)
A large and robust bivalve, the shell is oval in shape, the anterior end rounded, the posterior end more pointed. It has concentric ridges and is off-white, grey or light brown in colour. Shell length 15cm.
The Sand Gaper burrows to a depth of 50cm into mud and sandflats, where it filters organic matter from sea water. It is often found in estuaries, and is widespread and locally common.
Blunt Gaper (Mya truncata)
A thick-shelled, robust bivalve, rectangular in shape with a truncate posterior margin. It also has numerous concentric lines and is off-white in colour. Shell length up to 70mm.
It is commonly found in estuaries where it buries itself to a fair depth. Widespread and locally common, especially on the east coast of Britain.
Also called the ‘Irish Yellow Slug’, this is a medium-sized to large slug with a short keel. The body colour varies from pale ochre through to yellow-green to grey. The body has dark blotches or spots. The mucous is colourless. It has grey-blue tentacles. Similar to the Yellow Cellar Slug (Limacus flavus), which is a brighter yellow, has smaller spots and blotches, and has blue tentacles. Length 80 to 130mm.
It feeds on seedlings, vegetables, fungi, lichen, and decaying matter. It will even feed on pet food found indoors and old, damp wallpaper.
Commonly associated with gardens and houses, and it will venture indoors after dark. It prefers dark and moist habitats, and it may frequent cellars, greenhouses and sheds. Common and widespread throughout Britain and Ireland.
The shell of the Common Cockle is cream to pale yellow or brownish, and it has 22-28 radiating ribs crossed by prominant concentric ridges which may bare short spines. Length up to 5cm.
It is found in muddy, sandy and fine gravel shores, from the middle to lower shore. Utilising a muscular foot, it burrows up to 5cm into the sand, and when covered by water they open their shells and extend a pair of short siphons to filter-feed on zooplankton. It can live up to 10 years, and is fished commercially and prayed upon by wading birds. It is common and widespread.
Also known as the ‘Grove Snail’ or the ‘Banded Snail’, the lip of the shell is always dark brown. The shell colour is variable, from cream, yellow, brown or pink, and is often similar to the White-lipped Snail (Cepaea hortensis). Shell diameter 20 to 24mm.
Found in a range of habitats, but favours woodland, hedgerows, meadows and sand dunes. Also found in gardens. It feeds on a wide range of vegetation. Common and widespread throughout, except northern Scotland.
This mollusc has a shiny white to yellow, purple or greyish-brown slender wedge-shaped shell. Growth stages show as pale bands. The inner surfaces are tinted white, purple, yellow or orange. Length up to 38mm.
Found on the middle to lower shore where it burrows into coarse sand and lives just below the surface. The Banded Wedge Shell is a filter feeder, and when the tide is in it extracts food particles from the water via a syphon. Common and widespread on all British and Irish coasts, but less common further north on Scottish coastlines.
The shell is elongate, thin and brittle. There are numerous fine concentric lines, with a group of fine radiating striae. It is white or light brown, light olive or yellow. The hinge and ligament is positioned about a third of the way along the length of the mollusc. Length up to 130mm.
It burrows deeply in fine to medium course sands in the lower shore and shallow sublittoral. Found on the south-west coasts of England, Wales and Ireland.
Have you ever wondered what the underside of a limpet looked like? Note the large muscular foot, the relatively small mouth above, and the tentacles either side.
The Common Limpet has an ashen-grey or greenish-blue shell, sometimes with a yellow tint, and with radiating ridges. It is conical with an almost central apex. The shell is often covered in barnacles. The sole of the foot is yellowish or orange-brownish with a green tinge. Shell length 6cm. They are fairly long-lived, up to 15 years.
It inhabits the intertidal zone, clinging tightly to rocks along the shore or in rock pools, and with its thick shell it is able to withstand the pounding ocean waves, exposure to drying out, and attacks from birds or fish. It grazes on algae growing on the rocks beneath the water. It is not ‘stuck’ in one position as it may always appear to be, but follows a mucous trail as it feeds and finds it way back. Scarring maybe evident on the substrate where it has ground it down to get the perfect fit. Common and widespread around the British coasts.
Also called the ‘Blue Mussel’, the shells are dark brown, blue-black, or purple in colour. Shell length up to 10cm.
It is found middle to lower shore, and attaches itself to rocks via byssus threads. It will also find crevices in the rocks, or attach themselves to manmade structures like piers and harbour walls. They can form large beds up to 6 layers thick and covering many square kilometres. Mussels are filter feeders of plankton, pumping large amounts of water through their bodies to extract the food.
Very common and widespread all around the British coast.
This is an edible marine mussel which has been harvested by humans for centuries. They are a rich source of protein, and are very important to the marine life ecosystem.
We often find the remains of the cuttlefish shell called the ‘cuttlebone’ washed upon our shores, rather than the animal itself. It is a casting of the dead animal, and is a white, hard brittle internal structure, which is filled with gas to help the cuttlefish remain buoyant. The cast cuttlebone is often given to pet birds and reptiles as a source of calcium.
Cuttlefish have very large eyes and mouths like beaks. The body is wide and flattened, and a fin runs from behind the body from the head. There are eight arms encircling the mouth with suckers, which helps the cuttlefish to manipulate its prey. It also has two other tentacles which help the creature to snare its prey. It has amazing abilities of camouflage, and can change its colour to blend in with any surrounding. It can grow up 45cm in length.
It feeds on small fish, crabs, molluscs, and other species of cuttlefish, even its own. When threatened the Common Cuttlefish releases an ink known as sepia to produce a protective cloud about itself to confuse predators. Cuttlefish are one of the most intelligent of all invertebrates, and belong with the same group of molluscs as the octopuses and squids. It can live between 1 to 2 years.
The cuttlebone is often found washed up on beaches, where as the creature itself lives in the shallows to depths of 200m. It is common and widespread.
Also called the ‘Edible Periwinkle’, the shell is variable in colour, from black and grey to brown, white or red, and usually patterned with spiral dark lines. It is conical in shape with a pointed apex. This is the largest British periwinkle, but is usually smaller than 50mm.
It favours rocky shores upper to lower zones with a good covering of seaweed. It can also be found in mud-flats or esturaries. The Common Periwinkle is a herbivore which grazes on seaweeds. Widespread and abundant throughout.
You only have to pop out into your garden on a rainy day, or venture out during the night hours to find one of these slippery creatures going for your plants. This morning I happened to move my bird bath and there he was, hunkered down and sheltered for the day. However I awoke him, and as grumpy as he was (he blew bubbles at me), he obliged me a photo shoot between rain showers.
The shell of this snail can be marbled brown, black or yellow-ochre, and has fine wrinkles. Shell diameter 40mm.
Individuals contain both reproductive organs and are capable of self-fertilisation, although cross-fertilisation is the normal way.
They live in quite varied habitats, from woodland and hedgerows, to gardens and allotments, where they can be serious pests. Mainly feeding nocturnally, or after rain, they consume various plants, and can do a lot of damage. Common and widespread throughout lowland Britain, absent from most of Scotland.
Photographs taken July 2016, rear garden, Staffordshire.
The colour of the shell of this small snail varies depending on its habitat, and it can be green, orange, yellow, brown or black. There are also banded and chequered patterned forms. The head tentacles of the animal have two lines along them. The shell is finely reticulate. Shell height up to 1.5cm.
Found on the middle to lower shower on large brown seaweeds such as Egg Wrack (Ascophyllum nodosum) and Toothed Wrack (Fucus serratus) on which it feeds. Common on widespread throughout.
Photographs taken August 2015, rockpool, Meadfoot Beach, Torquay, Devon.
I find it quite amazing what you can discover by the simple act of turning over a log.
Also called the ‘Rotund Disc Snail’, this is a very small snail with 6 tightly packed whorls. The flattened shell is reddish-brown with darker cross bands. The body of the animal is bluish black on the upperside and pale below. Shell diameter 7mm.
Found in gardens and woodland under rocks and logs, and amongst leaf litter. Common and widespread in lowland areas.
Photograph taken March 2014, found under log, rear garden, Staffordshire.
As much as I love my garden, these slimy creatures seem to love it more – they are slowly, but surely chomping their way through it!
The shell of this snail is quite variable, ranging from all over yellow to yellow with dark brown spiral bands. The lip of the shell is almost always white. Shell diameter 16 to 20mm.
They can live for up to 3 years, and are found in gardens, woods and hedgerows. It is actve during the day in wet and mild conditions, found resting or feeding on vegetation. Common and widespread throughout Britain and Ireland.
Photographs taken June 2014, rear garden, Staffordshire.